Microwave dielectric properties of (Zn 1/3B 2/3) 0.5(Ti 0.8M 0.2) 0.5O 2 (B = Nb 5+, Ta 5+, M = Sn 4+, Ge 4+) ceramics

Abstract

Dielectric properties of (Zn 1/3Nb (2− x)/3 Ta x/3 ) 0.5(Ti 0.8Sn 0.1Ge 0.1) 0.5O 2 ( x = 0, 1, 2) and/or (Zn 1/3Nb 1/3Ta l/3) 0.5(Ti 0.8Sn 0.2(l− y) Ge 0.2 y ) 0.5O 2 ( y = 0, 0.5, 1) were investigated at the microwave frequencies. For the compositions with single phase of rutile structure, the dielectric constant ( K) of specimens was not only dependent on the dielectric polarizabilities, but also on the bond length ratio of apical bond ( d apical ) to equatorial bond ( d equatorial ) of oxygen octahedron in the unit cell. Temperature coefficients of the resonant frequencies ( TCF) of the specimens with B = Nb 5+ and/or M = Sn 4+ was larger than those with B = Ta 5+ and/or M = Ge 4+. These results could be attributed to the changes of the degree of oxygen octahedral distortion. Quality factors ( Qf) of the specimens with B = Ta 5+ and/or M = Sn 4+ were larger than those with B = Nb 5+ and/or M = Ge 4+.